*{
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
body{
  padding: 20px;
}
p{
  border: 1px solid #ededed;
  margin: 20px 0;
  padding: 10px ;
}

.preView{
  border: 1px solid black;
  padding: 10px;
  margin: 30px auto;
}
.preView pre{
  white-space: pre;
}